Outdoor Air Quality
Frequently Asked Questions

What is smog?
What is Ground-Level Ozone (GLO)?

What are the chemical reactions that form Ozone?

Is there a difference between Ground-Level Ozone and Stratospheric Ozone?

What are Nitrogen Oxides (NOx)?

What are the sources of NOx?

What are Volatile Organic Compounds (VOCs)?

What are the sources of VOCs?

What is particulate matter?

What are the sources of particulate matter?

Who monitors air quality in Canada and Ontario?

What is the air quality index?

What are the Ambient Air Quality Criteria (AAQC)?

What is the Air Pollution index?

What are the current standards for Air Quality?

What are the health effects of Ground Level Ozone?

What problem does Ozone pose for plant and animal life?

What effect can Ozone have on structures and materials?

What are the health effects associated with Particulate Matter (PM)?

What are the health effects experienced when exercising in poor air quality?

Are children at higher risk?

Are the elderly at higher risk?

Are people with pre-existing respiratory symptoms at higher risk?

What are the seasonal and daily variations of Ozone?

What can I do to improve outdoor air quality?

• On the road

• At home

How can I reduce my exposure?

What can smog related problems do to the economy?

What is being done to improve air quality?

• Federal and Provincial action

• International action

• Provincial action

In the past the word smog has been used to describe the presence of smoke and fog in the air.  Today, it is more commonly used to describe the dirty or hazy air that has engulfed Canada’s major cities and rural areas, which can cause breathing problems.  Smog is more common in summer when it is sunnier and temperatures are hotter.  It is formed from a mixture of ground-level ozone, other gasses, and microscopic airborne particles.

Ground-level ozone (GLO) is a colourless and highly irritating gas that forms through a complex reaction of nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.  GLO is considered a secondary pollutant because it is produced when two primary pollutants, NOx and VOCs, react.

 There are a series of reactions that take place in order to form ozone:

1. NO_{2 +} ultraviolet light  à NO + O
    

2. O + O₂   à  0₃

 The reaction is reversed in the dark and ozone is destroyed:

3. NO + O₃   à   NO_{2  +} O₂

No.  Ozone is the same chemical in the stratosphere and near the ground, yet it can have different effects depending on where it is formed.  Ground-Level Ozone can be dangerous to the health of plants, animals, and humans whereas the layer of ozone in the stratosphere acts as a protective layer to humans, plants and animals by screening out harmful ultraviolet radiation from the sun.  This layer of ozone can be found in the upper atmosphere and is therefore called stratospheric ozone.

NO_x are a group of seven compounds that contain nitrogen and oxygen and are one of the main precursors for the formation of ozone. Some of these include Nitric Oxide (NO), Nitrogen dioxide (NO₂) and Nitrous Oxide (N₂O). The major source of NO_xin Ontario is the transportation sector and a majority of the remaining emissions comes from power generation, primary metal production, and incineration. NO_x may also come from natural sources, lightning and aerobic activity of soil bacteria.

Volatile Organic Compounds are compounds that contain carbon or organic gases and vapours that evaporate quickly into the air at regular temperatures.  Some of these include benzene, toluene, and ethylene.  The major anthropogenic source of VOC's in Ontario is the transportation sector, which contributes 31% of the VOC emissions in Ontario as well as industrial processes that involve combustion.  VOC's are usually released through evaporation of liquid fuels, solvents and organic chemicals (i.e. oil-based paint, gasoline fumes).

Particulate Matter refers to all airborne solid and liquid particles with the exception of pure water that range in the size of approximately 0.005 to 100 microns in diameter although only particles up to 40 microns are monitored as Total Suspended Particulate matter (TSP).  The chemical composition of TSP includes a broad range of materials, such as carbonates, silicates, oxides, sulphates, nitrates, trace metals, and organic carbon compounds.  Recently, health effects of particulate matter have been attributed to Inhalable Particles (IP) which are 10 microns in diameter or smaller (PM10).  PM20 originates from both natural and anthropogenic sources and is commonly divided into a coarse and a fine fraction.  The fine fraction consists of Respirable Particles (RP) and encompasses particle sizes of 2.5 microns or smaller (PM2.5); they can easily travel to the deepest parts of the lung while the coarser fraction of PM10 may be caught and expelled by the lining of bronchial tubes.

Particles can originate from both natural and anthropogenic sources.  Some of the principal sources of particulate matter released into the air because of human activity are industrial operations such as power stations, refineries, construction activities, and transportation.  Some of the natural sources include forest fires, plants, and wind erosion of soil.  Physical processes such as abrasion, grinding, or material handling are the main causes of the coarse fraction of PM10.  Combustion gases are the main source of acidic PM2.5 particulates.

Air pollution is measured by provincial, municipal and industrial organizations at many monitoring stations across Canada.  The province of Ontario benefits from one of the most comprehensive monitoring networks in North America with more than 200 sites capable of monitoring air quality across the province.  Monitoring by the Ontario Ministry of the Environment is accomplished by two branches: the Air Quality and Meteorology Section of the Environmental Monitoring and Reporting Branch conducts real time, continuous recordings of a broad range of contaminants such as ozone, sulphur dioxide, nitrogen oxides, and others.  The other department is the Standards Development Branch of the Ministry of the Environment which monitors air quality on an as needed basis to examine regional and topical pollution problems.

The Air Quality Index (AQI) is based upon air quality levels that are derived from measurements at 27 locations across the province including a location in Sarnia.  This index is used to provide communities with information on the current air quality in that particular area by reporting on six criteria air pollutants.  The six pollutants of the Air Quality Index are carbon monoxide, nitrogen dioxide, sulphur dioxide, suspended particulates, total reduced sulphur, and ozone. They are chosen for their adverse effects on the health of humans and the environment at high levels.

Ambient Air Quality Criteria are used to indicate the maximum acceptable level of the pollutant.  They are expressed as a concentration of the pollutant in a volume of ambient air that is measured over a specific duration; i.e. parts per billion for one-hour, eight-hours, 24-hours, etc.  Using the Ambient Air Quality Criteria, the hourly data from the 27 recording stations is then converted into the open-ended air quality index scale for each location.  The pollutant with the highest AQI number becomes the overall AQI for that particular location.

If levels of ground level ozone are forecast to exceed 80 ppb, the Ministry will issue an “Air Quality Advisory”.  This advisory expects poor air quality (AQI>50) for the next two days due to ozone caused by light SW winds, stagnant weather and sunny conditions.  It declares a “Spare The Air Day” and includes both environmental information as well as health information to advise the public of specific risks associated with exposure.  To obtain current AQI information visit the Ministry of the Environment’s web page at: www.ene.gov.on.ca.

The Air Pollution Index (API) is a legal tool used to trigger actions designed to reduce or prevent air pollution episodes.  It is a sub-index of the AQI; thus, if the API has the highest recorded level compared to other criteria pollutants, it will become the AQI.  The API is calculated at hourly intervals based on the previous 24-hour averages of SO₂ and TSP.  If the API reaches a value of 32 and adverse meteorological conditions are predicted for the following six hours an Air Pollution Advisory is issued.  A First Air Pollution Alert Level is achieved when the index reaches a level of 50 and 6 hours of adverse atmospheric conditions are forecast.  Once a first alert level is reached, owners of major sources are ordered to curtail operations.  A Second Air Pollution Alert Level is achieved if the index of 75 is reached and further curtailment may be ordered.  An Air Pollution Episode will occur at an API of 100.  If atmospheric conditions are not expected to improve for at least six hours owners of all sources will be ordered by the Ministry of Health to cease operation.

At present, the Ontario Ministry of Environment (M.O.E.) uses a combination of standards, guidelines, and Ambient Air Quality Criteria (AAQC) in its air management program.  First, Point of Impingement (POI) standards and guidelines are established under Regulation 346.  This regulation requires that all new or altered potential sources of air contaminants get a Certificate of Approval from the M.O.E.  Certificates of Approval are issued if predicted half hour average concentrations of contaminants are lower than desirable concentrations at a hypothetical point of impingement.  POI regulations are subject to numerous exemptions and may be based on outdated mathematical models.  In addition to these POI standards, the M.O.E. also has a larger number of ambient air quality criteria and POI guidelines derived from AACQs.  These are used by the M.O.E. to assess general air quality and to define the potential for causing an adverse effect.  For example, operation of the AQI, the API, and the Air Quality Advisory is also regulated by Regulation 346.  Definition of AAQCs is accomplished under Regulation 337.  They are defined at a level not expected to cause adverse human health or environmental effects based on continuous exposure.  Appendix A is a list of the Point of Impingement Standards, Point of Impingement Guidelines and Ambient Air Quality Criteria.

Ozone can have a large array of short and long term adverse health effects on children, elderly and healthy individuals.  Short term exposure of low levels of ozone around one to two hours can irritate the eyes, nose and throat and produce respiratory complications such as coughing, wheezing and painful breathing.  Also, a reduction in lung function, resulting from an inflammatory response in the lung, has been seen in clinical short-term exposure studies as low as 82 ppb.  There has also been research that has indicated that long term exposure to ozone will decrease the lungs ability to ward off disease.  For example, Ground Level Ozone increases the susceptibility of asthmatics to common allergens.  Long term exposure to smog at low levels can affect lung elasticity and lung capacity effectively aging lungs prematurely.  Exposure may ultimately lead to an increase in hospital admissions and possibly premature death.

Ground Level Ozone has also been linked to adverse environmental effects to both plants and animals.  GLO can interfere with the ability of plants to produce food by damaging leaf tissue.  This accounts for approximately 10 to 40% growth loss, premature aging and a decrease in crop yields by as much as 20%.  Ozone sensitive crops include beans, tomatoes, tobacco, potatoes, corn, soya beans and wheat.  It is estimated that crop losses in Ontario due to damage from ozone are between $30 and $70 million annually.  Ozone can affect animals in the same way it does humans, by decreasing lung capacity and lung elasticity.

Ground Level Ozone can also have damaging effects on human produced material such as rubber and synthetic rubber products.  At low levels of exposure for a few months, ozone can cause cracks in products made of these materials.  Continued exposure will cause disintegration.  Ozone can also damage the integrity of cotton, acetate, nylon, and other textile fibres.

Most of the adverse health effects that are experienced from particulate matter are specific to the cardio-respiratory system.  The lung is the principal organ affected by particulates.  Particle size is most important from a perspective of human health.  The smaller a particle, the deeper it can penetrate into the lung and thus the greater the risk of a negative health effect.  Health effects associated with particles are:

• premature death within two days of exposure to relatively low sulphate levels,

• respiratory related hospital admissions and emergency admissions and emergency room visits,

• asthma attacks and respiratory irritation

• acute exposure may cause narrowing of airways

• chronic exposure may cause chronic bronchitis

• decreased lung function, and

• work and school absences.

Even moderately exercising healthy adults can experience 15 to 20% reductions in lung function from exposure to low levels of ozone over several hours.  Damage to lung tissue may be caused by repeated exposure to ozone and this could result in a reduced quality of life as people age.  Results from animal studies indicate that repeated exposure to high levels of ozone for several months or more can produce permanent structural damage in the lungs.  People that are most at risk are those who are outdoors and moderately exercising during the summer as well as construction workers and other outdoor workers.

Exercising increases the risk of health damage from ozone because more air is breathed in and air is drawn in deeper into the lungs.  Also, when people exercise they tend to breathe through their mouth, bypassing the nasal passages, the body’s natural filter.  Studies have indicated that very low levels of ozone significantly reduce lung function and cause shortness of breath, chest tightness and wheezing.  A study that looked at 23 male cyclists between the ages of 18 and 37, who rode during early summer evenings showed that the cyclists had a larger decrease in lung function when ozone concentrations were higher.

 Children tend to be at a greater risk to the health effects of ozone exposure because they are more frequently outdoors and more active than adults during the summertime when ozone levels are the highest.  Children are the largest subgroup sensitive to the adverse health effects of air pollution due to their breathing patterns.  Small children are likely to inhale and retain greater quantities of particles per unit body weight than adults.

The elderly population, especially those with cardiac or respiratory diseases such as asthma, emphysema and chronic bronchitis, are especially sensitive to air pollutants.  A recent study showed that Particulate Matter (PM2.5, PM10) and sulphate fraction of PM2.5 were all positively  associated with respiratory emergency room visits for patients over 64 years of age in Montreal, Quebec.

It has been pointed out by the U.S. Environmental Protection Agency (EPA) that people with pre-existing lung disease such as bronchitis, asthma, and emphysema already suffer from decreased lung function and therefore cannot tolerate an additional reduction in lung function due to ozone.  Canadian epidemiological studies demonstrated that asthma visits to the emergency room increase by 33% with a lag time of two days when the daily ozone level of 75 ppm was exceeded.  Clinical studies indicate that asthmatics may experience adverse health effects when exposed to ambient levels of acidic aerosols.

 Because sunlight is a major catalyst for Ground-Level Ozone formation, ozone levels are typically the highest from May to September, between noon and early evening.

 On the road

• Keep your tires properly inflated.  Properly inflated tires increase fuel economy by as much as 5%.  Routinely check that the tires are inflated to the maximum pressure specified by the manufacturer.

• Don’t idle when stopped.  Ten seconds of idling uses more fuel than restarting your engine.  The Ontario Ministry of Transportation estimates that an idling gasoline vehicle uses about 2.2 litres of fuel per hour and that an idling diesel engine truck uses about 3 litres of fuel per hour.

• Watch your speed.  Transport Canada estimates that differences in driving style can lead to a 20% variation in fuel consumption.  Driving at moderate speeds and avoiding starts and stops uses less fuel.  At speeds above the highway limit of 100 km/h, the fuel loss is about 1% for each kilometre per hour over.

• Try not to use the air conditioning in your car for local trips.  Your car’s air conditioner can reduce gas mileage up to 20% in stop and go traffic but are efficient on the highway.

• Maintain your vehicle by getting regular tune-ups.  Proper tuning of your car not only increases fuel economy by up to 10% but it also reduces air pollution.

• When buying a new car shop for Low Emission Vehicles (LEV), a designation available in some late model cars.  Consider alternative fuels such as propane or natural gas, or buy smaller vehicles to reduce pollution.

• Use public transportation or car-pool instead of using your car.  A bus load of passengers saves nine tons of air pollution each year.  Try walking, rollerblading or cycling.

• Postpone refuelling your car until after 6 p.m.  This reduces emissions during peak daylight hours when ozone formation is most likely to occur.  Don’t add gas after the pump automatically shuts off; this will avoid spills of gas and unnecessary VOC emissions.

At Home

• Avoid using garden tools that run on gasoline (lawnmower, leaf blower). On a per engine basis these machines emit much higher amounts of NOx, CO and hydrocarbons than automobiles.  The best option is to use rakes, push or electric mowers.

• Use water based (latex) paint rather than oil based variety.  Oil based paints contain three to five times more toxic solvents than water based paints.

• Don’t burn trash; try re-cycling or composting.

• Become energy efficient by insulating your home, it will reduce summer cooling costs and winter heating bills.

• People with respiratory illness such as asthma or chronic bronchitis, children and the elderly should avoid going outdoors during periods of high air pollution.

• Get air quality information by calling the Air Quality Index at 1-800-387-7768 and by watching the weather channel.  Newspapers and radio broadcasts should also provide air quality updates and smog advisories.

• Avoid exercising outdoors, especially in the afternoon when smog levels are high.

• Become a concerned environmental citizen.

• Become involved at school, Northern collegiate offers a “Partners in Air Program” that addresses hands on air quality issues.

• Contact local officials; community leaders need to hear from people who are concerned about local air pollution and the relevant risks.

• Make sure that teachers, coaches and recreation officials know about air pollution and its health effects and act accordingly.  Suggest the rescheduling of events if they fall on smog advisory days or days with high pollution levels.

Smog can have a major impact to many aspects of our economy.  The health problems that are associated with smog may lead to higher health care costs.  Smog causes losses of an estimated $70 million per year to crops.  Materials and structures may become damaged due to increased exposure and the forest industry will be affected due to the damage of a variety of trees that make up Canada’s forestry industry such as red and sugar maples from increased levels of ozone.

Federal Action

The federal government protects the health of Canadians from toxic substances and other pollutants through the 1999 Canadian Environmental Protection Act (CEPA).  Pollution prevention is the cornerstone of the new act; which, under federal jurisdiction, includes international affairs, motor vehicle emissions and fuel standards, and control of toxic substances.  Air quality related federal initiatives are the Federal Smog Management Plan, the Cleaner Vehicles and Fuels Initiative, the Motor Vehicle Safety Act, Canada-Wide Standards for Air Pollution, and international initiatives.

Provincial Action

Ontario regulates air quality issues through Regulations 337 and 346 of the Environmental Protection Act.  Major provincial activities focus on ambient air quality monitoring, emissions of vehicles after they have been sold to consumers and Certificates of Approval for industrial emitters.  Air quality related initiatives of the provincial government are Ontario’s Smog Plan and the continuing development and enforcement of AAQCs and point of impingement standards.